Midrash su Levitico 14:35

3) "for a possession": (not) until they conquer it. Whence is it derived that if they conquered it, but did not yet divide it (among the tribes); if they divided it (among the families), but did not yet apportion it into patrimonies and each did not clearly recognize his own — I might think that they would be subject to plague-spot tumah; it is, therefore, written (Vayikra 14:35) "Then he whose house it is shall come" — each must recognize what is his.

7) (Vayikra 14:35) ("Then he whose house it is shall come, and he shall tell the Cohein, saying: As a plague-spot there has appeared to me in the house.") "whose house it is": He shall not send a messenger. I might think, even if he were old or sick; it is, therefore, written he shall come" (connoting one who can come on his own power). "and he shall tell the Cohein": The Cohein shall make a close inquiry as to how the plague-spot came to his house. "saying": The Cohein shall tell him of recondite matters: "My son, plague-spots come only because of slander, as it is written (Devarim 24:8) "Be heedful of the plague-spot of leprosy to take great care and to do … (Devarim 24:9) "Remember what the L–rd your G d did to Miriam …" What does one have to do with the other? We are hereby taught that she was punished (with leprosy) only because of the other.

8) Now does it not follow a fortiori: If this is what happened to Miriam who spoke thus of Moses out of his presence, then one who speaks demeaningly of his neighbor to his face, how much more so!"